Conventionally, a hazardous liquid chemical may be used to polish a compound semiconductor substrate (wafer). For example, for an SiC substrate, HF may be used. Also, For a GaAs substrate, harmful arsenic may be mixed into a polishing waste liquid. Thus, in a conventional substrate polishing apparatus, a polishing environment is locally isolated and exhaust is carried out by a down flow system, preventing the leakage of a toxic substance to the outside. For example, Japanese Patent Laid-Open No. 2008-166709 describes such a technology.
However, in the conventional substrate polishing apparatus, it is necessary to improve tightness and enhance an exhaust volume in each portion of the apparatus, so that it becomes necessary to make significant design changes. Therefore, it has been desired to develop an apparatus capable of preventing the diffusion of a hazardous gas effectively without a significant design change.
A substrate polishing apparatus of one embodiment includes a polishing table having a polishing surface in an upper surface, a substrate holding portion that holds a substrate having a surface to be polished in a lower surface and presses the surface to be polished of the substrate against the polishing surface of the polishing table to polish the surface to be polished of the substrate, and a holding portion cover that covers an outer side of the substrate holding portion, in which between a lower portion of the holding portion cover and the upper surface of the polishing table, a gap portion for intake is provided, and in an upper portion of the holding portion cover, a pipe for exhaust connected to an exhaust mechanism is provided, and by operating the exhaust mechanism, a rising air current from the gap portion toward the pipe is formed between an outer surface of the substrate holding portion and an inner surface of the holding portion cover.
A substrate polishing apparatus of another embodiment includes a rotating polishing table, a substrate holding portion that holds a substrate and presses the substrate against the polishing table to polish the substrate, and a local exhaust mechanism whose intake head is disposed near the substrate holding portion, in which the intake head is disposed on a downstream side of the substrate holding portion in a rotation direction of the polishing table.